1. Field of the Invention
The present invention relates to a liquid crystal display apparatus provided with an illuminated dial or indicator sheet.
2. Description of Prior Art
A conventional liquid crystal display apparatus of this kind (in its exploded state) is shown in FIG. 3. Reference numeral 1 designates a liquid crystal cell, and 2 designates a back illuminating device comprising a combination of a reflector, a fluorescent lamp and a diffusion plate. Reference numeral 3 designates a light guide, 4 a dial sheet, and 5 a dial illuminating light source, for example, a light bulb. The light guide 3 comprises an opening 3A provided in the central portion of a flat plate, the display surface of the liquid crystal cell 1 facing to the opening 3A, and an incident portion 3B formed at one end of the light guide 3 to guide an emission light beam of the bulb 5 to the interior, said dial sheet 4 being attached to the upper surface of the light guide 3. The dial sheet 4 is formed with graduation lines, numerals, etc.
In the thus constructed liquid crystal display apparatus, when the apparatus is used at night, the dial illuminating light source 5 is lighted and the light emission therefrom is incident upon the light guide 3 to bring the graduation lines, numerals, etc. on the dial sheet 4 into relief (i.e., to make them visible). In that state, the liquid crystal cell 1 is actuated to read a display from the graduation lines, etc.
However, in the above-described structure, since the light source 5 is provided separately from the back illuminating device which illuminates the graduations, the number of parts increases, which entails great expense. In the case where a separate bulb is used for the dial illuminating light source 5, there poses a further problem of making it difficult to adjust a graduation illuminating color to a display color of the liquid crystal cell 1.